/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */


package javax.swing;

import javax.swing.plaf.*;
import javax.accessibility.*;

import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
import java.util.Objects;


/**
 * Used to display a "Tip" for a Component. Typically components provide api to automate the process
 * of using <code>ToolTip</code>s. For example, any Swing component can use the
 * <code>JComponent</code> <code>setToolTipText</code> method to specify the text for a standard
 * tooltip. A component that wants to create a custom <code>ToolTip</code> display can override
 * <code>JComponent</code>'s <code>createToolTip</code> method and use a subclass of this class. <p>
 * See <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/tooltip.html">How to Use
 * Tool Tips</a> in <em>The Java Tutorial</em> for further documentation. <p>
 * <strong>Warning:</strong> Swing is not thread safe. For more information see <a
 * href="package-summary.html#threading">Swing's Threading Policy</a>. <p> <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with future Swing releases. The current
 * serialization support is appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage of all JavaBeans&trade; has
 * been added to the <code>java.beans</code> package. Please see {@link java.beans.XMLEncoder}.
 *
 * @author Dave Moore
 * @author Rich Shiavi
 * @see JComponent#setToolTipText
 * @see JComponent#createToolTip
 */
@SuppressWarnings("serial")
public class JToolTip extends JComponent implements Accessible {

  /**
   * @see #getUIClassID
   * @see #readObject
   */
  private static final String uiClassID = "ToolTipUI";

  String tipText;
  JComponent component;

  /**
   * Creates a tool tip.
   */
  public JToolTip() {
    setOpaque(true);
    updateUI();
  }

  /**
   * Returns the L&amp;F object that renders this component.
   *
   * @return the <code>ToolTipUI</code> object that renders this component
   */
  public ToolTipUI getUI() {
    return (ToolTipUI) ui;
  }

  /**
   * Resets the UI property to a value from the current look and feel.
   *
   * @see JComponent#updateUI
   */
  public void updateUI() {
    setUI((ToolTipUI) UIManager.getUI(this));
  }


  /**
   * Returns the name of the L&amp;F class that renders this component.
   *
   * @return the string "ToolTipUI"
   * @see JComponent#getUIClassID
   * @see UIDefaults#getUI
   */
  public String getUIClassID() {
    return uiClassID;
  }


  /**
   * Sets the text to show when the tool tip is displayed.
   * The string <code>tipText</code> may be <code>null</code>.
   *
   * @param tipText the <code>String</code> to display
   * @beaninfo preferred: true bound: true description: Sets the text of the tooltip
   */
  public void setTipText(String tipText) {
    String oldValue = this.tipText;
    this.tipText = tipText;
    firePropertyChange("tiptext", oldValue, tipText);

    if (!Objects.equals(oldValue, tipText)) {
      revalidate();
      repaint();
    }
  }

  /**
   * Returns the text that is shown when the tool tip is displayed.
   * The returned value may be <code>null</code>.
   *
   * @return the <code>String</code> that is displayed
   */
  public String getTipText() {
    return tipText;
  }

  /**
   * Specifies the component that the tooltip describes.
   * The component <code>c</code> may be <code>null</code>
   * and will have no effect.
   * <p>
   * This is a bound property.
   *
   * @param c the <code>JComponent</code> being described
   * @beaninfo bound: true description: Sets the component that the tooltip describes.
   * @see JComponent#createToolTip
   */
  public void setComponent(JComponent c) {
    JComponent oldValue = this.component;

    component = c;
    firePropertyChange("component", oldValue, c);
  }

  /**
   * Returns the component the tooltip applies to.
   * The returned value may be <code>null</code>.
   *
   * @return the component that the tooltip describes
   * @see JComponent#createToolTip
   */
  public JComponent getComponent() {
    return component;
  }

  /**
   * Always returns true since tooltips, by definition,
   * should always be on top of all other windows.
   */
  // package private
  boolean alwaysOnTop() {
    return true;
  }


  /**
   * See <code>readObject</code> and <code>writeObject</code>
   * in <code>JComponent</code> for more
   * information about serialization in Swing.
   */
  private void writeObject(ObjectOutputStream s) throws IOException {
    s.defaultWriteObject();
    if (getUIClassID().equals(uiClassID)) {
      byte count = JComponent.getWriteObjCounter(this);
      JComponent.setWriteObjCounter(this, --count);
      if (count == 0 && ui != null) {
        ui.installUI(this);
      }
    }
  }


  /**
   * Returns a string representation of this <code>JToolTip</code>.
   * This method
   * is intended to be used only for debugging purposes, and the
   * content and format of the returned string may vary between
   * implementations. The returned string may be empty but may not
   * be <code>null</code>.
   *
   * @return a string representation of this <code>JToolTip</code>
   */
  protected String paramString() {
    String tipTextString = (tipText != null ?
        tipText : "");

    return super.paramString() +
        ",tipText=" + tipTextString;
  }

/////////////////
// Accessibility support
////////////////

  /**
   * Gets the AccessibleContext associated with this JToolTip.
   * For tool tips, the AccessibleContext takes the form of an
   * AccessibleJToolTip.
   * A new AccessibleJToolTip instance is created if necessary.
   *
   * @return an AccessibleJToolTip that serves as the AccessibleContext of this JToolTip
   */
  public AccessibleContext getAccessibleContext() {
    if (accessibleContext == null) {
      accessibleContext = new AccessibleJToolTip();
    }
    return accessibleContext;
  }

  /**
   * This class implements accessibility support for the
   * <code>JToolTip</code> class.  It provides an implementation of the
   * Java Accessibility API appropriate to tool tip user-interface elements.
   * <p>
   * <strong>Warning:</strong>
   * Serialized objects of this class will not be compatible with
   * future Swing releases. The current serialization support is
   * appropriate for short term storage or RMI between applications running
   * the same version of Swing.  As of 1.4, support for long term storage
   * of all JavaBeans&trade;
   * has been added to the <code>java.beans</code> package.
   * Please see {@link java.beans.XMLEncoder}.
   */
  @SuppressWarnings("serial")
  protected class AccessibleJToolTip extends AccessibleJComponent {

    /**
     * Get the accessible description of this object.
     *
     * @return a localized String describing this object.
     */
    public String getAccessibleDescription() {
      String description = accessibleDescription;

      // fallback to client property
      if (description == null) {
        description = (String) getClientProperty(AccessibleContext.ACCESSIBLE_DESCRIPTION_PROPERTY);
      }
      if (description == null) {
        description = getTipText();
      }
      return description;
    }

    /**
     * Get the role of this object.
     *
     * @return an instance of AccessibleRole describing the role of the object
     */
    public AccessibleRole getAccessibleRole() {
      return AccessibleRole.TOOL_TIP;
    }
  }
}
